Abstract: The model of coal and gas outburst shock wave is established based on the characteristics of coal and gas outburst and the correlation theory of aerodynamics. The gas expansion work is obtained through the theoretical calculation, and the simplified calculation of initial velocity is deduced by assuming that the protrusions do oblique movement. We propose the concept of “work potential difference”, namely coal and gas expansion work and the gravity potential difference and get the conclusion that the overpressure is proportional to the work potential difference. The fact is that the air speed is proportional to 1/2 power of the work potential difference and there is an exponential relationship between the overpressure of shock wave and gas pressure.